Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location

Health-enhancing physical activity interventions in non-ambulatory people with severe motor impairments - a scoping review

PURPOSE Non-ambulatory people with severe motor impairments due to chronic neurological diagnoses are forced into a sedentary lifestyle. The purpose of this scoping review was to understand the type and amount of physical activity interventions performed in this population as well as their effect. METHODS PubMed, Cochran and CINAHL Complete were systematically searched for articles describing physical activity interventions in people with a chronic, stable central nervous system lesion. The outcome measures needed to include physiological or psychological variables, measures of general health or quality of life. RESULTS Of the initial 7554 articles, 34 were included after the title, abstract, and full-text screening. Only six studies were designed as randomized-controlled trials. Most interventions were supported by technologies, mainly functional electrical stimulation (cycling or rowing). The duration of the intervention ranged from four to 52 weeks. Endurance and strength training interventions (and a combination of both) were performed and over 70% of studies resulted in health improvements. CONCLUSIONS Non-ambulatory people with severe motor impairments may benefit from physical activity interventions. However, the number of studies and their comparability is very limited. This indicates the need for future research with standard measures to develop evidence-based, specific recommendations for physical activity in this population.Key messagesPhysical activity interventions can have health benefits in non-ambulatory people with severe motor impairments. Even simple, low-tech interventions allow for health-enhancing training

Biomechanical analysis of the knee during an immersive, high-intensity exergame training in healthy athletes

Introduction: Exergaming – physically active gaming – is cognitively and physically challenging, and, therefore, has great potential for sports rehabilitation, for example after knee injuries. Before it can be recommended for rehabilitation, the biomechanics during exergaming needs to be understood. The occurrence of high-risk movement patterns for knee injuries, an abducted, internally rotated knee at 10-30° of flexion, needs to be monitored [1,2]. This study aimed to compare the amount of knee valgus (KV) and knee internal rotation (KIR) at 10-30° of knee flexion during different exercises of an immersive, high-intensive exergame in healthy athletes. Materials and Methods: Kinematics during a 25-minute exergame training (ExerCube) [3] were measured using marker-based motion capture (Vicon) in 18 athletes (9 female, 9 male) without prior knee injuries. The mean maximal KV and KIR angle during 10°- 30° knee flexion were compared between 9 exercises [4] using a two-way within-subject linear mixed model with post-hoc t-test. Results: A significantly higher KV compared to the other exercises, was found during the punch to the ipsilateral side of the investigated knee (Mean 8.5° (Standard Deviation 0.04°)) and high-touch to the contralateral side (8.5° (0.1°)). In addition, the ipsilateral KIR of the punch (13.2° (0.9°)), the high-touch (11.7° (0.6°)), and mid-touch (10.9° (1.3°)) were significantly larger than in the other exercises. Conclusion: High-touches, mid-touches, and punches result in knee kinematics related to an increased risk of injury in healthy athletes. The inclusion of these movements during exergame-based rehabilitation should be carefully managed and performed in later stages of rehabilitation

Basic functionality of a prototype wearable assistive soft exoskeleton for people with gait impairments : a case study

XoSoft is a soft modular wearable assistive exoskeleton for peo- ple with mild to moderate gait impairments. It is currently being developed by a European Consortium (www.xosoft.eu) and aims to provide tailored and active lower limb support during ambu- lation. During development, user-centered design principles were followed in parallel with the aim of providing functional support during gait. A prototype was developed and was tested for practi- cability, usability, comfort and assistive function (summarized as basic functionality) with a potential end user. The prototype con- sisted of a garment, electromagnetic clutch-controlled elastic bands supporting knee- and hip flexion and a backpack containing the sensor and actuator control of the system. The participant had ex- perienced a stroke and presented with unilateral impairment of the lower and upper extremities. In testing, he donned and doffed the prototype independently as far as possible, and performed walk- ing trials with the system in both active (powered on) and pas- sive (powered off) modes. Afterwards, the participant rated the perceived pressure and various elements of usability. Results high- lighted aspects of the system for improvement during future phases of XoSoft development, and also identified useful aspects of proto- type design to be maintained. The basic functionality of XoSoft could be assumed as satisfactory given that it was the first version of a working prototype. The study highlights the benefits of this participatory evaluation design approach in assistive soft robotics development

Surface electromyographic activity of trunk muscles during trunk control exercises for people after stroke; effect of a mobile and stable seat for rehabilitation

The aim of this study was to explore differences in trunk muscle activity on a stable and mobile seat for people after stroke and healthy participants. Trunk control exercises are known to have a beneficial effect on trunk control, balance, and mobility after stroke. The effect of such exercises could be enhanced by the use of a mobile seat to provide further training stimuli. However, little research on the musculoskeletal effects of trunk training on mobile seats has been carried out. On a stable and a mobile seat, thirteen people after stroke and fifteen healthy participants performed two selective trunk control exercises, which were lateral flexion initiated by the pelvis and the thorax. The maximal surface electromyography relative to static sitting of the muscles multifidus, erector spinae, and obliquus externus was recorded bilaterally. The effects of group, seat condition, trunk control exercise, and muscle side were investigated employing within-subject linear-mixed-models. Compared to the stable seat, the maximal muscle activity of people after stroke on the mobile seat was higher during the thorax-initiated exercise and lower during the pelvis-initiated exercise. Healthy participants showed opposite results with higher muscle activity on the mobile seat during the pelvis-initiated exercise. For trunk control training on a mobile seat with high muscle activation people after stroke should perform trunk control exercises initiated by the thorax, for training with lower muscle activity people after stroke should initiate selective trunk movements by the pelvis. The results can support the planning of progressive trunk control rehabilitation programs

Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location.Peer Reviewe

Health-enhancing physical activity interventions in non-ambulatory people with severe motor impairments – a scoping review

AbstractPurpose Non-ambulatory people with severe motor impairments due to chronic neurological diagnoses are forced into a sedentary lifestyle. The purpose of this scoping review was to understand the type and amount of physical activity interventions performed in this population as well as their effect.Methods PubMed, Cochran and CINAHL Complete were systematically searched for articles describing physical activity interventions in people with a chronic, stable central nervous system lesion. The outcome measures needed to include physiological or psychological variables, measures of general health or quality of life.Results Of the initial 7554 articles, 34 were included after the title, abstract, and full-text screening. Only six studies were designed as randomized-controlled trials. Most interventions were supported by technologies, mainly functional electrical stimulation (cycling or rowing). The duration of the intervention ranged from four to 52 weeks. Endurance and strength training interventions (and a combination of both) were performed and over 70% of studies resulted in health improvements.Conclusions Non-ambulatory people with severe motor impairments may benefit from physical activity interventions. However, the number of studies and their comparability is very limited. This indicates the need for future research with standard measures to develop evidence-based, specific recommendations for physical activity in this population.Key messagesPhysical activity interventions can have health benefits in non-ambulatory people with severe motor impairments.Even simple, low-tech interventions allow for health-enhancing training

Comparison of biomechanical risk factors for ACL injury between patients and healthy subjects during exergaming

Introduction Exergaming - physically active gaming - offers great potential for rehabilitation after knee injuries in sports, as it combines physical and cognitive challenges. However, before its use in sports rehabilitation can be recommended as safe and reliable, it is necessary to assess the biomechanics associated with knee injuries - an abducted, internally rotated knee at 10-30° of flexion (Koga et al., 2010). The aim of this study was to compare knee valgus (KV) during 10-30° knee flexion between healthy individuals without previous knee injuries and patients undergoing rehabilitation after knee injuries in three exercises of a high-intensive, immersive exergame (ExerCube). Methods The kinematics of 18 healthy subjects (25.2 ± 3.3 years, 9 female) and 6 patients (25.0 ± 5.9 years, 2 female) were recorded using marker-based movement analysis (Vicon) during 25 minutes of exergame training (Sphery Racer, ExerCube). The average maximum KV angle during 10-30° knee flexion was compared between healthy subjects and patients in the squat, jump, and burpee for the right leg using a linear mixed model. Results The average maximal KV in the squat was 4.3° for healthy subjects and 4.8° for patients. In the jump, an average maximal KV of 5.9° (healthy subjects) and 6.8° (patients) was found. With an average of 6.9° in the maximal KV of healthy subjects and 8.6° in patients, the burpee showed the highest KV of all exercises. A significant main effect was found for exercise (F(2, 45) = 57.03, p < .001), but not for the difference between groups (F(1, 22) = 0.45, p = 0.51). Discussion/Conclusion There are no significant differences in KV between healthy participants and patients undergoing rehabilitation after knee injuries. This indicates that the pre-injury movement pattern was restored in the patients, and it can be assumed that the studied exercises during exergaming are safe for use in this stage of rehabilitation. References Koga, H., Nakamae, A., Shima, Y., Iwasa, J., Myklebust, G., Engebretsen, L., Bahr, R., & Krosshaug, T. (2010). Mechanisms for noncontact anterior cruciate ligament injuries: Knee joint kinematics in 10 injury situations from female team handball and basketball. The American Journal of Sports Medicine, 38(11), 2218–2225. https://doi.org/10.1177/036354651037357

Evaluation of a passive exoskeleton for static upper limb activities

The aim of this study was to evaluate the effect of a passive upper body exoskeleton on muscle activity, perceived musculoskeletal effort, local perceived pressure and subjective usability for a static overhead task. Eight participants (4 male, 4 female) held a load (0 kg and 2 kg) three times overhead for a duration of 30 s each, both with and without the exoskeleton. Muscle activity was significantly reduced for the Biceps Brachii (49%) and Medial Deltoid (62%) by the device for the 2 kg load. Perceived effort of the arms was significantly lower with the device for the 2 kg load (41%). The device did not have a significant effect on trunk or leg muscle activity (for the 2 kg load) or perceived effort. Local perceived pressure was rated below 2 (low pressure levels) for all contact areas assessed. Half of the participants rated the device usability as acceptable. The exoskeleton reduced muscle activity and perceived effort by the arms, and had no significant negative effect on the trunk and lower Body with regards to muscle activity, perceived effort and localised discomfort

Writing through the labyrinth: Using l’ecriture feminine

Metaphors enable us to understand organisations in distinctive ways and explain the paucity of women in leadership positions, and yet, when gender discrimination is addressed via metaphor, women’s responses, resistance and agency are rarely included in such analyses. In this article, I employ a narrative writing practice inspired by the work of He´le`ne Cixous as a way of exploring how we might research and write differently in leadership studies. Cixous invites women to reclaim their sexuality and subjectivity through a feminine mode of women’s writing and what she defines as l’ecriture feminine can be interpreted as a liberating bodily practice that aims to release women’s repressed creative agency and transform phallogocentric structures. Using the Greek mythology of the Minotaur and the Labyrinth, this article weaves together these seemingly disparate concepts of myth, metaphor and feminist writing practices with leadership discourse to explore the ways in which academic women experience the university organisation as a labyrinth, how they navigate pathways to promotion and practice leadership. This creative analytic operates as a metanarrative that offers new ways of researching and writing leadership studies from the body, and reveals how myths continue to influence present experiences and structures in unexpected ways